Effect of trituration on dimensional changes of dental amalgam

The dimensional changes of dental amalgams during setting was evaluated using different methods of specimen production, and measurement procedures. Amalgam specimens were prepared from 10 commercially available dental amalgam alloys by mechanical condensation. Dimensional change was measured on microcators with a measuring load of 1 g. The variation in dimensional change with trituration was substantial, and similar to the difference between various brands of alloys at the same trituration time. Porosity seems to vary between 0.1 and 0.6% independent of severity of trituration except for two alloys in which increased trituration time seemed to reduce porosity. It was therefore pointed out that even though trituration in most cases can be altered to make an amalgam expand, such procedures should not be followed since optimal values of other clinically significant properties may not be maintained.